function over(name) {
  if(document.images) {
    document.images[name].src = "pix/"+name+"_over.jpg";
  }
}
function out(name) {
  if(document.images) {
  	document.images[name].src = "pix/"+name+".jpg";
  }
}

function openpopup(open_url, window_name, width, height, allow_scrolling) { 
  	var winl = (screen.width - width) / 2;
    var wint = (screen.height - height) / 2;
    popup = window.open(open_url,window_name,'toolbar=no,scrollbars='+allow_scrolling+',resizable=no,top='+wint+',left='+winl+',width='+width+',height='+height);
    popup.focus();
}